Physical activity mediates the relationship between fruit and vegetable consumption and cognitive functioning: a cross-sectional analysis

Background Excess adiposity is associated with impairments in cognitive functioning, whereas physical activity (PA) and fruit and vegetable consumption (FVC) may be protective against cognitive decline. Therefore, this study investigated the interrelationships between FVC, body mass index ( BMI), PA and cognitive functioning in younger and older adults. Methods Cross-sectional data of 45 522 participants (>= 30 years) were examined from the 2012 annual component of the Canadian Community Health Survey. Cognitive function was assessed using a single six-level question of the Health Utilities Index. PA was classified according to the Physical Activity Index kilocalories per kilogram per day as active, moderately active and inactive; BMI was measured in kg/m(2) and FVC (servings/day) was classified as low, moderate or high. To assess the interrelationship between FVC, BMI, PA, age and cognitive functioning, general linear models and mediation analyses were used. Results Higher BMIs, lower PA and FVC were associated with poorer cognitive functioning. Additionally, PA statistically mediated the relationship between FVC and cognitive function ( Sobel test: t = -3.15; P < 0.002); and higher education levels and daily FVC were associated with better cognitive function ( P < 0.001). Conclusion Higher PA levels were associated with better cognitive functioning in younger and older adults. Also, higher daily FVC and education levels were associated with better cognitive scores.